Association of cardiometabolic index with all-cause and cardiovascular mortality among middle-aged and elderly populations

The Cardiometabolic Index (CMI) is a well-recognized risk factor for a range of cardiovascular diseases and diabetes mellitus. However, the population-level characteristics of CMI and its potential association with mortality risk among individuals over 40 years of age have not been investigated. This study aims to assess the association between CMI and both all-cause and cardiovascular mortality among the middle-aged and elderly population. This cohort study utilized data from 3752 American adults extracted from the Sleep Heart Health Study (SHHS) conducted from 1995 to 2011. The CMI was calculated using the waist-to-height ratio, triglycerides (TG), and high-density lipoprotein cholesterol (HDL-C). The primary outcomes were all-cause mortality and cardiovascular mortality, with mortality data sourced from the SHHS Linked Mortality File. Kaplan-Meier survival curves and Cox regression models were employed to assess the prognostic value of the CMI. Among the 3752 American adults, the mean (SD) age was 65.9 (10.1) years, and 1969 (52.5%) were women. The mean (SD) CMI was 0.914 ± 0.939. Over an average follow-up period of 10.7 years, there were 926 all-cause deaths and 289 cardiovascular deaths. Participants were categorized into three groups based on their CMI levels: tertile (T) 1: 0.315 ± 0.0994; T2: 0.680 ± 0.128; T3: 1.75 ± 1.23. Multivariate Cox proportional hazards analysis showed that elevated CMI was significantly associated with all-cause mortality (HR 1.215, 95% CI 1.032-1.43 for T2; HR 1.309, 95% CI 1.115-1.537 for T3) and cardiovascular mortality (HR 1.305, 95% CI 0.971-1.755 for T2; HR 1.457, 95% CI 1.091-1.947 for T3). After adjusting for confounders, elevated CMI remained significantly associated with all-cause mortality (HR 1.315, 95% CI 1.098-1.575 for T3) and cardiovascular mortality (HR 1.562, 95% CI 1.124-2.17 for T3). Kaplan-Meier survival curves indicated significantly worse outcomes for participants in the higher CMI tertiles for both all-cause mortality (log-rank p = 0.0035) and cardiovascular mortality (log-rank p = 0.035). This national cohort study found that CMI is significantly associated with both all-cause and cardiovascular mortality among American adults aged over 40. These findings suggest that CMI could be a valuable tool for identifying high-risk individuals, thereby aiding in the implementation of targeted preventive strategies.